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1.5

Memory Organization

User data

(256 bits)

UID Number

(64 bits)

X

AFI

Password

0x06

0x08

0x09

0x0B

0x0A

Block Addr

0x00

0x01

0x02

32 bits

F U

F = Factory Lock, U = User Lock

Lock Bits

0x03

0x04

0x05

0x06

0x07

Memory Organization

According to ISO 15693 Up-Link communication (Transponder to Reader) can be accomplished with one

subcarrier (ASK modulation) or with two subcarrier (FSK modulation). Both modes (ASK and FSK) can

operate with either high or low data rate. The transponder answers in the mode it was interrogated

from the reader and supports all communication parameter combinations. Up- and Down-Link are

frame synchronized and CRC check sum secured.

Each Tag-it HF-I Pro Transponder IC has a ‘unique’ address (UID) stored in two blocks, which are

transponder uniquely and individually for a one-to-one exchange between the reader and the transponder.

A mechanism to resolve collisions of a multiplicity of transponders (Anticollision) is also implemented. This

special feature allows multiple transponders to be read simultaneously and offers the capability to

inventory, in a very short time, a large number of transponders by their unique address, provided they are

within the reader operating range.

Also, the Application Family Identifier (AFI), which is optional in the ISO15693 is supported by the Tag-it

HF-I Pro Transponder.

For more details about the communication between reader and transponder see ISO/IEC 15693 and the

Tag-it HF-I Pro Extended Command Specification.

User data is read and stored in a 256 bit non-volatile user memory that is organized in 8 blocks. Each

block with 32 bit is user programmable and can be locked individually to protect data from modification.

Once set, the lock bit cannot be reset. The user memory is field programmable per block. Two levels of

block locking are supported: Individual block locking by the user (U) or individual block locking of factory

programmed data (F) during manufacturing. Bit 2 of the “Block Security Status” Byte defined in ISO

15693-3 is used to store the Factory Lock Status of the Block. Factory Block locking irreversibly protects

the locked data from any further reprogramming. User locked blocks can be reprogrammed by use of the

password protected write command.

Figure 1-2. Memory Organization of the Tag-it HF-I Pro Transponder IC

SCBU045 (11-09-21-065) – October 2007

Introduction

9

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